3. Cleanliness of the fluid : Never re-use fluid that has been in service Il.- DIFFERENT TYPES OF PIPING 1. Metal piping : There are three sizes of metal pipe : - 4,5 mm external diameter ~ 6.35 mm external diameter - 3.5 mm external diameter - Only use standard pipes as supplied by the Replacement Parts. Department; except for the pipes running the length of the chassis- all the pipes are ready to be fitted. - Pipes which have been pressure-rested are marked with a coloured sleeve, Red for LHS2 systems, and Green for LHM. They must be used only on cars using the appropriate fluid.